A key is an important constituent part of an electronic device such as a mobile. Reference is made to FIG. 1, which is a schematic structural diagram of a key of an electronic device in a conventional technology. The key includes a key cap 1′ and a substrate 2′. The key cap 1′ is a component playing a role of decoration and press function on the top of the key. The substrate 2′ is connected to a circle under the key cap 1′, whose area is a little more than an area of the key cap 1′. The substrate 2′ is a component for fixing the key cap 1′ on the electronic device to prevent the key cap 1′ from falling off.
The key cap 1′ and the substrate 2′ are formed integrally in conventional technology. It is difficult to form an integral key with many special materials, for example, using glass to manufacture integrally the key cap 1′ and the substrate 2′ has a complex craftwork, and structural strength of the integral key cap 1′ and substrate 2′ is low. Therefore, selection of a material of the key is quite limited due to the limitation of the craftwork. Generally only a plastics key or a metal key may be selected. For the plastics key or the metal key, generally they need to be made very thick to satisfy requirement on strength or the like. A relatively large space is needed to arrange the key, which is not consistent with a design concept of an electronic device with a small size and light mass.
In view of this, for the above technical problem, it is urgent to optimize the key of the electronic device in the conventional technology, so that the selection of the material is flexible and a thickness and an occupation of the space are reduced under a premise that the requirement on strength or the like is satisfied.